Recently, the safety analysis methodology for an intermediate break loss of coolant accident (IBLOCA) has been developing in SPACE code team in South Korea. It is stem from elimination of a large break loss of coolant accident (LBLOCA) strategy in a design basis event. In order to understand major phenomena and to check capability of SPACE code for an IBLOCA, Large Scale Test Facility(LSTF) tests no. 2 and no.7 are selected one of separate effect tests (SETs) for the IBLOCA. Before conducting benchmark calculations, a PIRT for IBLOCA is achieved. Thus, major phenomena are defined, and their importance and knowledge levels are identified. The preliminary calculations of the LSTF test no.2 and no.7 shows that break flow is well predicted by SPACE code. However, the peak cladding temperature is under-estimated, which is highly related to the behavior of core level. In addition, accumulator model has poor prediction for injection rate, which needs to be improved in order to better prediction of the core level. And sensitivity test for various model parameters, including critical flow model, discharge coefficient of a critical flow model, multi-dimensional core modeling, and so on. Multi-dimensional core modeling shows different results from previous studies. The one of additional influential phenomenon to the core water level is a CCFL. In the near future, intensive sensitivity study including CCFL will be conducted to obtain improved model of the LSTF for IBLOCA.